Imagine that you fired up your computer and found that a bunch of your programs no longer worked, because behind the scenes, the operating system had been upgraded without any backwards compatibility. That’s what happened this week with Google. Some things that were working just fine now are broken, because Google isn’t being backwards compatible. And that’s fairly unprecedented.

Don’t panic. One of the changes really shouldn’t hurt many sites, impacting only a “power SEO” technique commonly called PageRank sculpting that I’d say fairly few use. The other has a bigger impact and potentially means thousands of sites may now be violating Google’s rules on paid link without knowing it. But that’s not likely to have an immediate impact. I’ll explain both changes in more depth below.

The most important thing is that in both cases, the changes may require site owners to alter their web sites not because they were “chasing the algorithm” but instead because they were following Google’s own rules and instructions. They were doing what was advised, and now they may have to undo that work.

That’s the unprecedented part. Google has constantly upgraded how it deals with site content, from early advances like indexing PDF documents to later changes like showing “sitelinks” for web sites. These upgrades have been generally good and involved little to no work on the part of the site owner, until now.

PageRank Sculpting: Spending A Page’s Authority Money

Let’s take PageRank sculpting. In general, every individual web page that Google finds has some degree of importance that the page can pass on to other pages — PageRank. Links from that page to other pages are how it passes that importance along. And in its most basic, earliest form, each link on the page equally shared some of the importance.

Consider it like this. Imagine authority is money, and a particular page has $10 in “authority” to spend. It links out to 10 pages, so each of those pages gets $1 ($10 divided by 10). If it links to 20 pages, each gets 50 cents ($10 divided by 20). If it links to 5 pages, each page gets $2 (you get the math by now).

With PageRank sculpting, the idea is to effectively block some of the links on your web page (using the nofollow attribute or some other means) from getting any authority. Perhaps you have a lot of navigational links to other pages inside your web site. Rather than spend authority money on these pages, you might prefer to spend it on a smaller number of important pages that could use a boost.

PageRank Sculpting Gets Popular

This technique has been around for ages and had various names until the middle of 2007. That’s when it went more mainstream in the advanced SEO space. And in particular, it went that way I feel because Google spam fighting czar Matt Cutts talked about how Google’s YouTube was using PageRank sculpting during an open discussion at Google with a variety of advanced SEO people about techniques and issues.

I recall it being described as a means to ensure your best pages got the most PageRank. I also recall being kind of annoyed about it (and think I said so during the meeting). For years, we’d been told that site owners shouldn’t have to do extraordinary things to help search engines. Good page titles, good ability to be crawled, sure. But having to think about things on a link-by-link basis? That’s something I assumed Google was already up to snuff about. My assumption had been that Google long decided to discount how much credit it assigned to things like navigational links, when it could see the same links appearing on multiple pages within the same web site.

Now to be clear, it’s not like Matt told everyone in the room to immediately do PageRank sculpting. Many topics were discussed, and this was just one of many things covered. But it was advice that came from Google — and it turned into a genie that wouldn’t go into the bottle.

Soon after, Rand Fishkin at SEOmoz did an article about the topic, and more soon followed on the web. It was a topic at conferences. It was a hot new fashion in SEO. And while plenty in the SEO space will chase after the latest (and often useless) algorithm fad — this was a chase sparked by Google itself. Why wouldn’t advanced people do it?

PageRank Sculpting Gets Debated

Not everyone agreed it was helpful. There’s been quite a bit of debate on whether it gives boost or not. Somehave argued against using it at all. And the search engines, when asked about it since it gained popularity, have generally said that there are other things that are better worth the effort. But neither had they ruled it out. As I summarized last year:

I agree with the view that sculpting is a marginal activity compared to other things that can be done. But if you’re an advanced SEO — even someone advanced in terms of working with design issues — maybe it’s not so marginal. The search engines themselves are saying it has some value. They’ve not said it’s a flat out waste of time. And if you’ve mastered all the other things that are much more important, then yes, something like this may very well be worth giving more attention to.

Or as Michael Gray explained, if you’re driving a beat-up old car of a web site, putting a PageRank sculpting “engine” in it probably isn’t worthwhile. But if you’ve got a hot new sports car, well….

PageRank Sculpting Gets Depreciated

So today at SMX Advanced, sculpting was being discussed, and then Matt Cutts dropped a bomb shell that it no longer works to help flow more PageRank to the unblocked pages. Again — and being really simplistic here — if you have $10 in authority to spend on those ten links, and you block 5 of them, the other 5 aren’t going to get $2 each. They’re still getting $1. It’s just that the other $5 you thought you were saving is now going to waste.

Further, it was explained that YouTube wasn’t doing sculpting way back in 2007 as a way to boost certain video content. Instead, it was that YouTube randomly shows some video content and didn’t want these random selections to perhaps gain more authority than they should. And even with the change announced today, that still works. In the past, the unblocked videos got more authority money and the blocked ones got none. Now, the unblocked videos still get authority money — just not as much — and the blocked ones still get none.

But while that may be how it works on YouTube, I still recall PageRank sculpting being positioned by Google as a way to also give some pages more link juice. To quote Matt when asked about this in an official Google thread:

What are some appropriate ways to use the nofollow tag? One good example is the home page of expedia.com. If you visit that page, you’ll see that the “Sign in” link is nofollow’ed. That’s a great use of the tag: Googlebot isn’t going to know how to sign into expedia.com, so why waste that PageRank on a page that wouldn’t benefit users or convert any new visitors? Likewise, the “My itineraries” link on expedia.com is nofollow’ed as well. That’s another page that wouldn’t really convert well or have any use except for signed in users, so the nofollow on Expedia’s home page means that Google won’t crawl those specific links.

Most webmasters don’t need to worry about sculpting the flow of PageRank on their site, but if you want to try advanced things with nofollow to send less PageRank to copyright pages, terms of service, privacy pages, etc., that’s your call.

I’ve bolded the key part. Matt stresses — as he’s consistently done since talking about this at the SEO meeting — that this is something most people didn’t need to worry about or do. But saying “why waste that PageRank” means that at the time of giving this advice, PageRank was something that could be “saved” and “spent” on other pages.

You can expect Matt will do a blog post to cover this topic more. You can expect lots of people to be analyzing the change, and what it might or might not mean. And you should really understand that it was never the case that links shared equally in the amount of authority money a page had. In talking with Matt during the “You & A Session” at SMX Advanced, he confirmed that Google itself makes many determinations of how exactly a page can spend that authority money. IE — while a page might have $10 to spend, Google itself largely acts as the page’s investment banker, not the page’s author.

I wouldn’t panic and immediately start removing nofollow attributes that have been done for PageRank sculpting purposes. In general, I’d never recommend changing anything to a site that seems to be performing well. Take the time to let more discussion and information come from Google and other sources.

JavaScript onClick & Paid Link Worries

Those who PageRank sculpted following Google’s advice may have spent time doing something that no longer will work, or work as effectively, but they’ve not necessarily wasted time. Maybe it was helping them some in the past (plenty believe this). And they might not have to spend time removing it, any more than there are plenty of sites that still have meta keywords tags in place even though widespread search engine support of this was dropped long ago. That’s good depreciation, or effectively backwards compatibility. No one needs to change anything because the sites still keep “working” despite the past support being gone.

Links in JavaScript that were invisible to Google before are now being read. And some people have used JavaScript as a way to deliver paid links in a way that don’t violate Google’s guidelines may not technically on the wrong side of the Google law. It’s been a long accepted practice that this was a “safe” way to deal with paid links, once that Google’s suggested itself.

It’s as if Google has suddenly passed a new safety helmet law for web sites, mandating that the old helmets they’d been using are no longer good enough. Now they need to do something different.

What about nofollow? After all, Google’s been pushing nofollow as something sites should do as a safety device for paid links long after paid links themselves had been in existence.

True, and there are plenty of sites out there that have never caught up with this new Google guideline (and still sucky for those who really still innocently don’t know better). But that’s different than sites that thought they were doing the right thing and now which have to change again.

For the record, Matt said today that there’s no immediate penalties likely to be given out. Honestly, I think the spam team is still having to digest how to handle this change that’s been brought about by Google’s crawling team. And he also said that the nofollow attribute can be applied to JavaScript links that are not otherwise being redirected through a robots.txt block.

As I said in the case of PageRank sculpting, I wouldn’t immediately panic. But unlike with PageRank sculpting, if you’re selling paid links and thought JavaScript was protecting you, I would fairly quickly ensure that redirects are blocked by using nofollow within the JavaScript itself or by going through a robots.txt block.

(For an example of this, our paid links get delivered through JavaScript generated by Google Ad Manager. The links all get redirected through this domain — http://googleads.g.doubleclick.net — and you can see from the robots.txt file there that search engines aren’t allowed to crawl it. So, the links pass no authority on to other pages)

Backwards Compatibility Is Important

Overall, I want Google to keep advancing. But it needs to ensure that the changes don’t dramatically cause more work for site owners, as a result. We need a period of backwards compatibility in terms of Google indexing, just as much as it’s helpful with computer operating systems.

For more about the discussions today out of SMX Advanced, also see these selected stories from the live blogging round-up: